FIGURE 1.

Interleukin 4 (IL4) protects midbrain dopaminergic (mDA) neurons from MPP⁺-induced neurodegeneration in mixed neuron-glia cultures. E14 ventral midbrain neuron-enriched cultures (A) and E14 ventral midbrain mixed neuron-glia cultures (C) were treated with 0.2 μM MPP⁺ in the presence or absence of IL4 (10 ng/ml) for 2 days and numbers of TH⁺ neurons were counted. Scale bars indicate 50 μm. Quantifications and statistical evaluations revealed that IL4 failed to protect mDA neurons in E14 neuron-enriched cultures (B) but was sufficient to significantly protect mDA neurons in E14 mixed neuron-glia cultures (D). Data are given as mean ± SEM from four (neuron-enriched cultures) and five (neuron-glia cultures) independent experiments performed in duplicates. P-values derived from one-way ANOVA followed by Bonferroni’s multiple comparison post-test are ^∗p < 0.05, ^∗∗p < 0.01 and ^∗∗∗p < 0.001.